Spunbond web material with improved tactile softness attributes

ABSTRACT

A nonwoven web formed of spunlaid fibers comprising a first polyolefin, a second polyolefin, and a softness enhancer additive is disclosed. The nonwoven web is impressed with a first pattern of bond impressions defining a second pattern of unbonded raised regions, and has undergone a hydrogengorgement process following a calendar bonding process. Also disclosed is an absorbent article in which the nonwoven web is a component.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/968,415, filed Mar. 21, 2014, the substance of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The business of manufacturing and marketing disposable absorbentarticles for personal care or hygiene (such as disposable diapers,training pants, adult incontinence undergarments, feminine hygieneproducts, breast pads, care mats, bibs, wound dressing products, and thelike) is relatively capital intensive and highly competitive. Tomaintain or grow their market share and thereby maintain a successfulbusiness, manufacturers of such articles must continually strive toenhance their products in ways that serve to differentiate them fromthose of their competitors, while at the same time controlling costs soas to enable competitive pricing and the offering to the market of anattractive value-to-price proposition.

One way in which some manufacturers may seek to enhance such products isthrough enhancements to softness. Parents and caregivers naturally seekto provide as much comfort as they can for their babies, and utilizingproducts such as disposable diapers that they perceive as relativelysoft provides reassurance that they are doing what they can to providecomfort in that context. With respect to other types of disposableabsorbent articles that are designed to be applied and/or worn close theskin, an appearance of softness can reassure the wearer or caregiverthat the article will be comfortable.

Thus, manufacturers may devote efforts toward enhancing the softness ofthe various materials used to make such products, such as various webmaterials, including nonwoven web materials formed from polymer fibers,and laminates thereof, forming the products. Such laminates may include,for example, laminates of polymer films and nonwoven web materialsforming the backsheet components of the products.

It is believed that humans' perceptions of softness of a nonwoven webmaterial can be affected by tactile signals, auditory signals and visualsignals.

Tactile softness signals may be affected by a variety of the material'sfeatures and properties that have effect on its tactile feel, includingbut not limited to loft, fiber thickness and density, basis weight,microscopic pliability and flexibility of individual fibers, macroscopicpliability and flexibility of the nonwoven web as formed by the fibers,surface friction characteristics, number of loose fibers or free fiberends, and other features.

Perceptions of softness also may be affected by auditory signals, e.g.,whether and to what extent the material makes audible rustling,crinkling or other noises when touched or manipulated.

It is believed that perceptions of softness of a material also may beaffected by visual signals, i.e., its visual appearance. It is believedthat, if a nonwoven material looks relatively soft to a person, it ismuch more likely that the person will perceive it as having relativetactile softness as well. Visual impressions of softness may be affectedby a variety of features and properties, including but not limited tocolor, opacity, light reflectivity, refractivity or absorption, apparentthickness/caliper, fiber size and density, and macroscopic physicalsurface features.

As a result of the complexity of the mix of the above-describedcharacteristics, to the extent softness is considered an attribute of anonwoven web material, it may elude precise measurement orquantification. Although several methods for measuring and evaluatingmaterial features that are believed to affect softness signals have beendeveloped, there are no standard, universally accepted units or methodsof measurement for softness. It is a subjective, relative concept,difficult to characterize in an objective way. Because softness isdifficult to characterize, it can also be difficult to affect in apredictable way, through changes or adjustments to specifications inmaterials or manufacturing processes.

Complicating efforts to define and enhance softness is the fact thatdiffering individuals will have differing individual physiological andexperiential frames of reference and perceptions concerning whatmaterial features and properties will cause them to perceive softness toa lesser or greater extent in a material, and relative other materials.

Various efforts have been made to provide or alter features of nonwovenweb materials with the objective of enhancing consumer perceptions ofsoftness. These efforts have included selection and/or manipulation offiber chemistry, basis weight, loft, fiber density, configuration andsize, tinting and/or opacifying, embossing or bonding in variouspatterns, etc.

These approaches have had varying degrees of success, but have left roomfor improvement in enhancing visual and/or tactile softness signals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a disposable diaper shown laid outhorizontally in a relaxed state, wearer-facing surfaces up;

FIG. 1B is a plan view of a disposable diaper shown laid outhorizontally in a stretched out, flattened state (stretched out againstelastic contraction induced by the presence of elastic members),wearer-facing surfaces facing the viewer;

FIG. 2A is a cross section of the diaper depicted in FIGS. 1A and 1B,taken through line 2-2 in those figures;

FIG. 2B is a schematic cross section of a portion of a laminate of apolymeric film and a nonwoven web, taken through a path of bondimpressions;

FIG. 3A is a schematic depiction of a pattern(s) that may be machined,etched, engraved or otherwise formed on the working surface of acalender-bonding roller;

FIG. 3B is a schematic depiction of a pattern(s) of bond impressionsthat may be impressed on a nonwoven web;

FIG. 4A is an image of a nonwoven web sample taken using equipmentdescribed in the Average Measured Height Method set forth herein,illustrating an outline of an unbonded area; and

FIG. 4B is an image of a nonwoven web sample taken using equipmentdescribed in the Average Measured Height Method set forth herein,illustrating outlines of individual bond impressions.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Absorbent article” refers to devices that absorb and contain bodyexudates, and, more specifically, refers to devices that are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Absorbent articles mayinclude diapers, training pants, adult incontinence undergarments andpads, feminine hygiene products, breast pads, care mats, bibs, wounddressing products, and the like. As used herein, the term “exudates”includes, but is not limited to, urine, blood, vaginal discharges,breast milk, sweat and fecal matter.

“Absorbent core” means a structure typically disposed between a topsheetand backsheet of an absorbent article for absorbing and containingliquid received by the absorbent article. The absorbent core may alsoinclude a cover layer or envelope. The cover layer or envelope maycomprise a nonwoven. In some examples, the absorbent core may includeone or more substrates, an absorbent polymer material, and athermoplastic adhesive material/composition adhering and immobilizingthe absorbent polymer material to a substrate, and optionally a coverlayer or envelope.

“Absorbent polymer material,” “absorbent gelling material,” “AGM,”“superabsorbent,” and “superabsorbent material” are used hereininterchangeably and refer to cross linked polymeric materials that canabsorb at least 5 times their weight of an aqueous 0.9% saline solutionas measured using the Centrifuge Retention Capacity test (Edana441.2-01).

“Absorbent particulate polymer material” is used herein to refer to anabsorbent polymer material which is in particulate form so as to beflowable in the dry state.

“Absorbent particulate polymer material area” as used herein refers tothe area of the core wherein the first substrate and second substrateare separated by a multiplicity of superabsorbent particles. There maybe some extraneous superabsorbent particles outside of this area betweenthe first substrate 64 and second substrate.

“Airfelt” is used herein to refer to comminuted wood pulp, which is aform of cellulosic fiber.

“Average Measured Height” is an average difference in z-direction heightbetween raised, unbonded areas, and bond impressions, of a nonwoven webcomponent of a laminate of a polymeric film and a nonwoven web, measuredand calculated according to the Average Measured Height Method set forthherein.

A “batt” is used herein to refer to fiber materials prior to beingconsolidated in a final calendering process as described herein. A“batt” comprises individual fibers, which are usually unbonded to eachother, although a certain amount of pre-bonding between fibers may beperformed and is also included in the meaning, such as may occur duringor shortly after the lay-down of fibers in a spunlaying process, or asmay be achieved be a pre-calendering. This pre-bonding, however, stillpermits a substantial number of the fibers to be freely moveable suchthat they can be repositioned. A “batt” may comprise several strata,such as may result from depositing fibers from several beams in aspunlaying process.

“Bicomponent” refers to fiber having a cross-section comprising twodiscrete polymer components, two discrete blends of polymer components,or one discrete polymer component and one discrete blend of polymercomponents. “Bicomponent fiber” is encompassed within the term“Multicomponent fiber.” A Bicomponent fiber may have an overall crosssection divided into two or more subsections of the differing componentsof any shape or arrangement, including, for example, coaxialsubsections, core-and-sheath subsections, side-by-side subsections,radial subsections, etc.

“Bond Area Percentage” on a nonwoven web is a ratio of area occupied bybond impressions, to the total surface area of the web, expressed as apercentage, and measured according to the Bond Area Percentage methodset forth herein.

“Bond Length Ratio” is a value expressed as percentage, and is the ratioof the sum of lengths of a repeating series of bond impressions on anonwoven web along a theoretical line segment through and connecting thebond impressions in the series, and extending from a leading edge of thebond impression beginning the series, to a leading edge of the bondimpression beginning the next adjacent repeating series, to the totallength of the line segment, and is determined according to the BondPath/Bond Length Ratio measurement method set forth herein. By way ofnon-limiting illustration FIG. 3B in which length D₀ is the length of aline segment and lengths D₁, D₂ and D₃ are lengths along the linesegment of three bond impressions in a hypothetical repeating series ofsubstantially identical bond impressions 100 a as shown in FIG. 3B, aBond Length Ratio may be calculated as [(D₁+D₂+D₃)/D₀]×100%. It will benoted that if all bond impressions 100 a as exemplified in FIG. 3B areidentical in area, shape and spacing, any group of them in any numberalong a line segment will constitute a repeating series. However, bondimpressions forming a path also may have differing areas, shapes and/orspacing, and it may be necessary to identify a repeating series of bondimpressions of any other particular number in order to determine BondLength Ratio.

“Bonding roller,” “calender roller” and “roller” are usedinterchangeably.

A “bond impression” in a nonwoven web is the surface structure createdby the impression of a bonding protrusion on a calender roller into anonwoven web. A bond impression is a location of deformed, intermeshedor entangled, and melted or thermally fused, materials from fiberssuperimposed and compressed in a z-direction beneath the bondingprotrusion, which form a bond. The individual bonds may be connected inthe nonwoven structure by loose fibres between them. The shape and sizeof the bond impression approximately corresponds to the shape and sizeof the bonding surface of a bonding protrusion on the calender roller.

A “column” of bonds on a nonwoven web is a group of nearest neighboringbonds of like shape and rotational orientation that are arranged alongthe line that extends most predominately in the machine direction.

“Cross direction”(CD)—with respect to the making of a nonwoven webmaterial and the nonwoven web material, refers to the direction alongthe web material substantially perpendicular to the direction of forwardtravel of the web material through the manufacturing line in which theweb material is manufactured. With respect to a batt moving through thenip of a pair of calender rollers to form a bonded nonwoven web, thecross direction is perpendicular to the direction of movement throughthe nip, and parallel to the nip.

“Disposable” is used in its ordinary sense to mean an article that isdisposed or discarded after a limited number of usage events overvarying lengths of time, for example, less than about 20 events, lessthan about 10 events, less than about 5 events, or less than about 2events.

“Diaper” refers to an absorbent article generally worn by infants andincontinent persons about the lower torso so as to encircle the waistand legs of the wearer and that is specifically adapted to receive andcontain urinary and fecal waste. As used herein, term “diaper” alsoincludes “pant” which is defined below.

“Fiber” and “filament” are used interchangeably.

“Fiber diameter” is expressed in units of μm. The terms “grams of fiberper 9000 m” (denier or den) or “grams of fiber per 10000 m” (dTex) areused to describe the fineness or coarseness of fibers, which are linkedto the diameter (when assumed to be circular) by the density of theemployed material(s).

“Film”—means a skin-like or membrane-like layer of material formed ofone or more polymers, which does not have a form consistingpredominately of a web-like structure of consolidated polymer fibersand/or other fibers.

“Length” or a form thereof, with respect to a diaper or training pant,refers to a dimension measured along a direction perpendicular to thewaist edges and/or parallel to the longitudinal axis.

“Machine direction” (MD)—with respect to the making of a nonwoven webmaterial and the nonwoven web material, refers to the direction alongthe web material substantially parallel to the direction of forwardtravel of the web material through the manufacturing line in which theweb material is manufactured. With respect to a nonwoven batt movingthrough the nip of a pair of calender rollers to form a bonded nonwovenweb, the machine direction is parallel to the direction of movementthrough the nip, and perpendicular to the nip.

“Monocomponent” refers to fiber formed of a single polymer component orsingle blend of polymer components, as distinguished from bicomponent ormulticomponent fiber.

“Multicomponent” refers to fiber having a cross-section comprising morethan one discrete polymer component, more than one discrete blend ofpolymer components, or at least one discrete polymer component and atleast one discrete blend of polymer components. “Multicomponent fiber”includes, but is not limited to, “bicomponent fiber.” A multicomponentfiber may have an overall cross section divided into subsections of thediffering components of any shape or arrangement, including, forexample, coaxial subsections, core-and-sheath subsections, side-by-sidesubsections, radial subsections, islands-in-the-sea, etc.

A “nonwoven” is a manufactured sheet or web of directionally or randomlyoriented fibers which are first formed into a batt and then consolidatedand bonded together by friction, cohesion, adhesion or one or morepatterns of bonds and bond impressions created through localizedcompression and/or application of pressure, heat, ultrasonic or heatingenergy, or a combination thereof. The term does not include fabricswhich are woven, knitted, or stitch-bonded with yarns or filaments. Thefibers may be of natural or man-made origin and may be staple orcontinuous filaments or be formed in situ. Commercially available fibershave diameters ranging from less than about 0.001 mm to more than about0.2 mm and they come in several different forms: short fibers (known asstaple, or chopped), continuous single fibers (filaments ormonofilaments), untwisted bundles of continuous filaments (tow), andtwisted bundles of continuous filaments (yarn). Nonwoven fabrics can beformed by many processes including but not limited to meltblowing,spunbonding, spunmelting, solvent spinning, electrospinning, carding,film fibrillation, melt-film fibrillation, airlaying, dry-laying,wetlaying with staple fibers, and combinations of these processes asknown in the art. The basis weight of nonwoven fabrics is usuallyexpressed in grams per square meter (gsm).

“Opacity” is a numeric value relating to the ability of a web materialto transmit light therethrough, measured according the OpacityMeasurement Method set forth herein.

“Pant” or “training pant”, as used herein, refer to disposable garmentshaving a waist opening and leg openings designed for infant or adultwearers. A pant may be placed in position on the wearer by inserting thewearer's legs into the leg openings and sliding the pant into positionabout a wearer's lower torso. A pant may be preformed by any suitabletechnique including, but not limited to, joining together portions ofthe article using refastenable and/or non-refastenable bonds (e.g.,seam, weld, adhesive, cohesive bond, fastener, etc.). A pant may bepreformed anywhere along the circumference of the article (e.g., sidefastened, front waist fastened). While the terms “pant” or “pants” areused herein, pants are also commonly referred to as “closed diapers,”“prefastened diapers,” “pull-on diapers,” “training pants,” and“diaper-pants”. Suitable pants are disclosed in U.S. Pat. No. 5,246,433,issued to Hasse, et al. on Sep. 21, 1993; U.S. Pat. No. 5,569,234,issued to Buell et al. on Oct. 29, 1996; U.S. Pat. No. 6,120,487, issuedto Ashton on Sep. 19, 2000; U.S. Pat. No. 6,120,489, issued to Johnsonet al. on Sep. 19, 2000; U.S. Pat. No. 4,940,464, issued to Van Gompelet al. on Jul. 10, 1990; U.S. Pat. No. 5,092,861, issued to Nomura etal. on Mar. 3, 1992; U.S. Patent Publication No. 2003/0233082 A1,entitled “Highly Flexible And Low Deformation Fastening Device”, filedon Jun. 13, 2002; U.S. Pat. No. 5,897,545, issued to Kline et al. onApr. 27, 1999; U.S. Pat. No. 5,957,908, issued to Kline et al on Sep.28, 1999.

When used as an adjective in connection with a component of a material,the term “predominately” means that the component makes up greater than50% by weight of the material. When used as an adjective in connectionwith a directional orientation of a physical feature or geometricattribute thereof, “predominately” means the feature or attribute has aprojection onto a line extending along the direction indicated, greaterin length than the projection onto a line perpendicular thereto. Withinother context, the term “predominantly” refers to a condition whichimparts a substantial effect on a property or feature. Thus, when amaterial comprises “predominantly” a component said to impart aproperty, this component imparts a property that the material otherwisewould not exhibit. For example, if a material comprises “predominantly”heat-fusible fibers, the quantity and components of these fibers must besufficient to allow heat fusion of the fibers.

A “bonding protrusion” or “protrusion” is a feature of a bonding rollerat its radially outermost portion, surrounded by recessed areas.Relative the rotational axis of the bonding roller, a bonding protrusionhas a radially outermost bonding surface with a bonding surface shapeand a bonding surface shape area, which generally lies along an outercylindrical surface with a substantially constant radius from thebonding roller rotational axis; however, protrusions having bondingsurfaces of discrete and separate shapes are often small enough relativethe radius of the bonding roller that the bonding surface may appearflat/planar; and the bonding surface shape area is closely approximatedby a planar area of the same shape. A bonding protrusion may have sidesthat are perpendicular to the bonding surface, although usually thesides have an angled slope, such that the cross section of the base of abonding protrusion is larger than its bonding surface. A plurality ofbonding protrusions may be arranged on a calender roller in a pattern.The plurality of bonding protrusions has a bonding area per unit surfacearea of the outer cylindrical surface which can be expressed as apercentage, and is the ratio of the combined total of the bonding shapeareas of the protrusions within the unit, to the total surface area ofthe unit.

A “row” of bonds on a nonwoven web is a group of nearest neighboringbonds of like shape and rotational orientation that are arranged alongthe line that extends most predominately in the cross direction.

“Tensile Strength” refers to the maximum tensile force (Peak Force) amaterial will sustain before tensile failure, as measured by the TensileStrength Measurement Method set forth herein.

“Thickness” and “caliper” are used herein interchangeably.

“Total Stiffness” refers to the measured and calculated value relatingto a material, according to the Stiffness measurement method set forthherein.

“Width” or a form thereof, with respect to a diaper or training pant,refers to a dimension measured along a direction parallel to the waistedges and/or perpendicular to the longitudinal axis.

“Z-direction,” with respect to a web, means generally orthogonal orperpendicular to the plane approximated by the web in the machine andcross direction dimensions.

Absorbent Article

Examples of the present invention include disposable absorbent articleshaving improved softness attributes.

FIG. 1A is a perspective view of a diaper 10 in a relaxed, laid-openposition as it might appear opened and lying on a horizontal surface.FIG. 1B is a plan view of a diaper 10 shown in a flat-out, uncontractedstate (i.e., without elastic induced contraction), shown with portionsof the diaper 10 cut away to show underlying structure. The diaper 10 isdepicted in FIG. 1B with its longitudinal axis 36 and its lateral axis38. Portions of the diaper 10 that contact a wearer are shown orientedupwards in FIG. 1A, and are shown facing the viewer in FIG. 1B. FIG. 2Ais a cross section of the diaper taken at line 2-2 in FIG. 1B.

The diaper 10 generally may comprise a chassis 12 and an absorbent core14 disposed in the chassis. The chassis 12 may comprise the main body ofthe diaper 10.

The chassis 12 may include a topsheet 18, which may be liquid pervious,and a backsheet 20, which may be liquid impervious. The absorbent core14 may be encased between the topsheet 18 and the backsheet 20. Thechassis 12 may also include side panels 22, elasticized leg cuffs 24,and an elastic waist feature 26. The chassis 12 may also comprise afastening system, which may include at least one fastening member 46 andat least one landing zone 48.

The leg cuffs 24 and the elastic waist feature 26 may each typicallycomprise elastic members 28. One end portion of the diaper 10 may beconfigured as a first waist region 30 of the diaper 10. An opposite endportion of the diaper 10 may be configured as a second waist region 32of the diaper 10. An intermediate portion of the diaper 10 may beconfigured as a crotch region 34, which extends longitudinally betweenthe first and second waist regions 30 and 32. The crotch region 34 mayinclude from 33.3% to 50% of the overall length of the diaper 10, andeach of waist regions 30, 32 may correspondingly include from 25% to33.3% of the overall length of the diaper 10.

The waist regions 30 and 32 may include elastic elements such that theygather about the waist of the wearer to provide improved fit andcontainment (elastic waist feature 26). The crotch region 34 is thatportion of the diaper 10 which, when the diaper 10 is worn, is generallypositioned between the wearer's legs.

The diaper 10 may also include such other features including front andrear ear panels, waist cap features, elastics and the like to providebetter fit, containment and aesthetic characteristics. Such additionalfeatures are described in, e.g., U.S. Pat. Nos. 3,860,003 and 5,151,092.

In order to apply and keep diaper 10 in place about a wearer, the secondwaist region 32 may be attached by the fastening member 46 to the firstwaist region 30 to form leg opening(s) and an article waist. Whenfastened, the fastening system carries a tensile load around the articlewaist.

According to some examples, the diaper 10 may be provided with are-closable fastening system or may alternatively be provided in theform of a pant-type diaper. When the absorbent article is a diaper, itmay comprise a re-closable fastening system joined to the chassis forsecuring the diaper to a wearer. When the absorbent article is apant-type diaper, the article may comprise at least two side panelsjoined to the chassis and to each other to form a pant. The fasteningsystem and any component thereof may include any material suitable forsuch a use, including but not limited to plastics, films, foams,nonwoven, woven, paper, laminates, stretch laminates, activated stretchlaminates, fiber reinforced plastics and the like, or combinationsthereof. In some examples, the materials making up the fastening devicemay be flexible. In some examples, the fastening device may comprisecotton or cotton-like materials for additional softness or consumerperception of softness. The flexibility may allow the fastening systemto conform to the shape of the body and thus, reduce the likelihood thatthe fastening system will irritate or injure the wearer's skin.

For unitary absorbent articles, the chassis 12 and absorbent core 14 mayform the main structure of the diaper 10 with other features added toform the composite diaper structure. While the topsheet 18, thebacksheet 20, and the absorbent core 14 may be assembled in a variety ofwell-known configurations, preferred diaper configurations are describedgenerally in U.S. Pat. No. 5,554,145 entitled “Absorbent Article WithMultiple Zone Structural Elastic-Like Film Web Extensible Waist Feature”issued to Roe et al. on Sep. 10, 1996; U.S. Pat. No. 5,569,234 entitled“Disposable Pull-On Pant” issued to Buell et al. on Oct. 29, 1996; andU.S. Pat. No. 6,004,306 entitled “Absorbent Article WithMulti-Directional Extensible Side Panels” issued to Robles et al. onDec. 21, 1999.

The topsheet 18 may be fully or partially elasticized and/or may beforeshortened to create a void space between the topsheet 18 and theabsorbent core 14. Exemplary structures including elasticized orforeshortened topsheets are described in more detail in U.S. Pat. No.5,037,416 entitled “Disposable Absorbent Article Having ElasticallyExtensible Topsheet” issued to Allen et al. on Aug. 6, 1991; and U.S.Pat. No. 5,269,775 entitled “Trisection Topsheets for DisposableAbsorbent Articles and Disposable Absorbent Articles Having SuchTrisection Topsheets” issued to Freeland et al. on Dec. 14, 1993.

The backsheet 20 may be joined with the topsheet 18. The backsheet 20may serve prevent the exudates absorbed by the absorbent core 14 andcontained within the diaper 10 from soiling other external articles thatmay contact the diaper 10, such as bed sheets and clothing. Referring toFIG. 2B, the backsheet 20 may be substantially impervious to liquids(e.g., urine) and comprise a laminate of a nonwoven 21 and a thinpolymeric film 23 such as a thermoplastic film having a thickness ofabout 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils). Suitablebacksheet films include those manufactured by Tredegar Industries Inc.of Terre Haute, Ind. and sold under the trade names X15306, X10962, andX10964. Other suitable backsheet materials may include breathablematerials that permit vapors to escape from the diaper 10 while stillpreventing liquid exudates from passing through the backsheet 20.Exemplary breathable materials may include materials such as woven webs,nonwoven webs, composite materials such as film-coated nonwoven webs,and microporous films such as manufactured by Mitsui Toatsu Co., ofJapan under the designation ESPOIR and by EXXON Chemical Co., of BayCity, Tex., under the designation EXXAIRE. Suitable breathable compositematerials comprising polymer blends are available from ClopayCorporation, Cincinnati, Ohio under the name HYTREL blend P1 8-3097.Other examples of such breathable composite materials are described ingreater detail in PCT Application No. WO 95/16746, published on Jun. 22,1995 in the name of E. I. DuPont. Other breathable backsheets includingnonwoven webs and apertured formed films are described in U.S. Pat. No.5,571,096 issued to Dobrin et al. on Nov. 5, 1996.

In some examples, the backsheet may have a water vapor transmission rate(WVTR) of greater than about 2,000 g/24 h/m2, greater than about 3,000g/24 h/m2, greater than about 5,000 g/24 h/m2, greater than about 6,000g/24 h/m2, greater than about 7,000 g/24 h/m2, greater than about 8,000g/24 h/m2, greater than about 9,000 g/24 h/m2, greater than about 10,000g/24 h/m2, greater than about 11,000 g/24 h/m2, greater than about12,000 g/24 h/m2, greater than about 15,000 g/24 h/m2, measuredaccording to WSP 70.5 (08) at 37.8 OC and 60% Relative Humidity.

Various components of an absorbent article such as a diaper 10 may beformed of a nonwoven web material described herein, including but notnecessarily limited to the topsheet 18 and the nonwoven 21 component ofthe backsheet 20.

Soft Blend Resin

The nonwoven 21 may be formed from one or more resins of polyolefins,polyesters, polyamide including but not limited to polypropylene (PP),polyethylene (PE), and polyethylene terephthalate (PET), poly-lacticacid (PLA), and blends thereof. Resins including polypropylene may beparticularly useful because of polypropylene's relatively low cost andsurface friction properties of fibers formed from it (i.e., they have arelatively smooth, slippery tactile feel). Resins including polyethylenemay also be desirable because of polyethylene's relativesoftness/pliability and even more smooth/slippery surface frictionproperties. Relative each other, PP currently has a lower cost andfibers formed from it have a greater tensile strength, while PEcurrently has a greater cost and fibers formed from it have a lowertensile strength but greater pliability and a more smooth/slippery feel.Accordingly, it may be desirable to form nonwoven web fibers from ablend of PP and PE resins, finding a balance of the best proportions ofthe polymers to balance their advantages and disadvantages. In someexamples, the fibers may be formed of PP/PE blends such as described inU.S. Pat. No. 5,266,392. Nonwoven fibers may be formed of, or mayinclude as additives or modifiers, components such as aliphaticpolyesters, thermoplastic polysaccharides, or other biopolymers.

In one embodiment, the nonwoven 21 comprises at least a layer of fibersthat are made of a composition comprising a first polyolefin, a secondpolyolefin that is different than the first polyolefin and a softnessenhancer additive. In one embodiment, the first polyolefin may bepolypropylene homopolymer. It is found that a second polyolefincomprising a propylene copolymer can provide advantageous properties tothe resulting nonwoven. A “propylene copolymer” includes at least twodifferent types of monomer units, one of which is propylene. Suitableexamples of monomer units include ethylene and higher alpha-olefinsranging from C₄-C₂₀, such as, for example, 1-butene, 4-methyl-1-pentene,1-hexene or 1-octene and 1-decene, or mixtures thereof, for example.Preferably, ethylene is copolymerized with propylene, so that thepropylene copolymer includes propylene units (units on the polymer chainderived from propylene monomers) and ethylene units (units on thepolymer chain derived from ethylene monomers).

Typically the units, or comonomers, derived from at least one ofethylene or a C4-10 alpha-olefin may be present in an amount of 1% to35%, or 5% to about 35%, or 7% to 32%, or 8 to about 25%, or 8% to 20%,or even 8% to 18% by weight of the propylene-alpha-olefin copolymer. Thecomonomer content may be adjusted so that the propylene-alpha-olefincopolymer has preferably a heat of fusion (“DSC”) of 75 J/g or less,melting point of 100° C. or less, and crystallinity of 2% to about 65%of isotactic polypropylene, and preferably a melt flow rate (MFR) of 0.5to 90 dg/min.

In one embodiment, the propylene-alpha-olefin copolymer comprises ofethylene-derived units. The propylene-alpha-olefin copolymer may contain5% to 35%, or 5% to 20%, or 10% to 12%, or 15% to 20%, ofethylene-derived units by weight of the propylene-alpha-olefincopolymer. In some embodiments, the propylene-alpha-olefin copolymerconsists essentially of units derived from propylene and ethylene, i.e.,the propylene-alpha-olefin copolymer does not contain any othercomonomer in an amount typically present as impurities in the ethyleneand/or propylene feedstreams used during polymerization or an amountthat would materially affect the heat of fusion, melting point,crystallinity, or melt flow rate of the propylene-alpha-olefincopolymer, or any other comonomer intentionally added to thepolymerization process.

The propylene-alpha-olefin copolymer may have a triad tacticity of threepropylene units, as measured by 13C NMR, of at least 75%, at least 80%,at least 82%, at least 85%, or at least 90%. The “Triad tacticity” isdetermined as follows. The tacticity index, expressed herein as “m/r”,is determined by 13C nuclear magnetic resonance (“NMR”). The tacticityindex m/r is calculated as defined by H. N. Cheng in 17 MACROMOLECULES1950 (1984), incorporated herein by reference. The designation “m” or“r” describes the stereochemistry of pairs of contiguous propylenegroups, with “m” referring to meso and “r” referring to racemic. An m/rratio of 1.0 generally describes a syndiotactic polymer, and an m/rratio of 2.0 generally describes an atactic material. An isotacticmaterial theoretically may have a m/r ratio approaching infinity, andmany by-product atactic polymer have sufficient isotactic content toresult in an m/r ratio of greater than 50.

The propylene-alpha-olefin copolymer may have a heat of fusion (“Hf”),as determined by Differential Scanning calorimetry (“DSC”), of 75 J/g orless, 70 J/g or less, 50 J/g or less, or even 35 J/g or less. Thepropylene-alpha-olefin copolymer may have a Hf of at least 0.5 J/g, 1J/g, or at least 5 J/g. The “DSC” is determined as follows. About 0.5grams of polymer is weighed and pressed to a thickness of about 15 to 20mils (about 381-508 microns) at about 140-150° C., using a “DSC mold”and MYLAR™ film as a backing sheet. The pressed polymer sample isallowed to cool to ambient temperatures by hanging in air (the MYLAR™film backing sheet is not removed). The pressed polymer sample is thenannealed at room temperature (about 23-25° C.) for 8 days. At the end ofthis period, a 15-20 mg disc is removed from the pressed polymer sampleusing a punch die and is placed in a 10 microliter aluminum sample pan.The disc sample is then placed in a DSC (Perkin Elmer Pyris 1 ThermalAnalysis System) and is cooled to −100° C. The sample is heated at about10° C./min to attain a final temperature of 165° C. The thermal output,recorded as the area under the melting peak of the disc sample, is ameasure of the heat of fusion and can be expressed in Joules per gram(J/g) of polymer and is automatically calculated by the Perkin Elmersystem. Under these conditions, the melting profile shows two maxima,the maximum at the highest temperature is taken as the melting pointwithin the range of melting of the disc sample relative to a baselinemeasurement for the increasing heat capacity of the polymer as afunction of temperature.

The propylene-alpha-olefin copolymer may have a single peak meltingtransition as determined by DSC. In one embodiment, the copolymer has aprimary peak transition of 90° C. or less, with a broad end-of-melttransition of about 110° C. or greater. The peak “melting point” (“Tm”)is defined as the temperature of the greatest heat absorption within themelting range of the sample. However, the copolymer may show secondarymelting peaks adjacent to the principal peak, and/or at the end-of-melttransition. For the purposes of this disclosure, such secondary meltingpeaks are considered together as a single melting point, with thehighest of these peaks being considered the Tm of thepropylene-alpha-olefin copolymer. The propylene-alpha-olefin copolymermay have a Tm of 100° C. or less, 90° C. or less, 80° C. or less, or 70°C. or less. The propylene-alpha-olefin copolymer may have a density of0.850 to 0.920 g/cm3, 0.860 to 0.900 g/cm3, or 0.860 to 0.890 g/cm3, atroom temperature as measured per ASTM D-1505.

The propylene-alpha-olefin copolymer may have a melt flow rate (“MFR”),as measured according to ASTM D1238, 2.16 kg at 230° C., of at least 0.2dg/min. In one embodiment, the propylene-alpha-olefin copolymer MFR is0.5 to 5000 dg/min, about 1 to 2500 dg/min, about 1.5 to 1500 dg/min, 2to 1000 dg/min, 5 to 500 dg/min, 10 to 250 dg/min, 10 to 100 dg/min, 2to 40 dg/min, or 2 to 30 dg/min.

The propylene-alpha-olefin copolymer may have an Elongation at Break ofless than 2000%, less than 1000%, or less than 800%, as measured perASTM D412.

The propylene-alpha-olefin copolymer may have a weight average molecularweight (Mw) of 5,000 to 5,000,000 g/mole, preferably 10,000 to 1,000,000g/mole, and more preferably 50,000 to 400,000 g/mole; a number averagemolecular weight (Mn) of 2,500 to 2,500,00 g/mole, preferably 10,000 to250,000 g/mole, and more preferably 25,000 to 200,000 g/mole; and/or az-average molecular weight (Mz) of 10,000 to 7,000,000 g/mole,preferably 80,000 to 700,000 g/mole, and more preferably 100,000 to500,000 g/mole. The propylene-alpha-olefin copolymer may have amolecular weight distribution (“MWD”) of 1.5 to 20, or 1.5 to 15,preferably 1.5 to 5, and more preferably 1.8 to 5, and most preferably1.8 to 3 or 4. The “Molecular weight (Mn, Mw, and Mz)” and “MWD” can bedetermined as follows and as described in Verstate et al., 21MACROMOLECULES 3360 (1988). Conditions described herein govern overpublished test conditions. Molecular weight and MWD are measured using aWaters 150 gel permeation chromatograph equipped with a Chromatix KMX-6on-line light scattering photometer. The system is used at 135[deg.] C.with 1,2,4-trichlorobenze as the mobile phase. Showdex (Showa-DenkoAmerica, Inc.) polystyrene gel columns 802, 803, 804, and 805 are used.This technique is discussed in Verstate et al., 21 MACROMOLECULES 3360(1988). No corrections for column spreading are employed; however, dataon generally acceptable standards, e.g., National Bureau of StandardsPolyethylene 1484, and anionically produced hydrogenated polyisoprenes(an alternating ethylenepropylene copolymer) demonstrate that suchcorrections on Mw/Mn or Mz/Mw are less than 0.05 units. Mw/Mn wascalculated from an elution time-molecular relationship whereas Mz/Mw wasevaluated using the light scattering photometer. The numerical analysiscan be performed using the commercially available computer softwareGPC2, MOLWT2 available from LDC/Milton Roy-Rivera Beach, Fla. Examplessuitable propylene-alpha-olefin copolymers are available commerciallyunder the trade names VISTAMAXX® (ExxonMobil Chemical Company, Houston,Tex., USA), VERSIFY® (The Dow Chemical Company, Midland, Mich., USA),certain grades of TAFMER® XM or NOTIO® (Mitsui Company, Japan), andcertain grades of SOFTEL® (Basell Polyolefins of the Netherlands). Theparticular grade(s) of commercially available propylene-alpha-olefincopolymer suitable for use in the invention can be readily determinedusing methods applying the selection criteria in the above.

Propylene copolymers have a good mixability with propylene homopolymers,where depending on the mutual ratio of both constituents it is possibleto prepare a material exhibiting various properties. A propylenecopolymer is soft to touch and the nonwoven textile produced from it hasgood drapeability and is easy to bend. On the other hand polypropyleneprovides strength and reduces the plasticity of the material. Examplesof composition that are suitable for the manufacturing of fibrousnonwoven materials can include at least 60%, at least 70%, at least 75%,or at least 80% by weight of the composition of polypropylenehomopolymer, and at least 10%, at least 12%, at least 14% by weight ofthe propylene copolymer. The described composition is generally drapableand soft but also maintains the required mechanical properties. Howeverit is found that it can feels rough to the touch and can be described as“rubbery.” In particular, propylene-alpha-olefin copolymers,particularly propylene-ethylene copolymers, can be tackier thanconventional fibers made from polyolefins such as polyethylene andpolypropylene.

Softness Enhancer Additive

It is found that the addition of a softness enhancer additive can beadvantageous to reduce the tacky or rubbery feel of fibers that are madeof a composition that includes a blend of the first and secondpolyolefin previously described. The softness enhancer additivegenerally imparts a relatively silky (reduced friction) feel to thefibers. The softness enhancer additive may be added to the compositionin neat form, diluted, and/or as a masterbatch in, for example,polyolefin polymers such as polypropylene, polystyrene, low densitypolyethylene, high density polyethylene, or propylene-alpha-olefincopolymers.

A composition suitable to make fibers as described herein contains oneor more softness enhancer additive, which can be present in an amount ofbetween 0.01% to 10%, or between 0.03% to 5%, or even between 0.05% to1% by weight of the fibers. Once the fiber are spun to form a nonwoven,some of the softness enhancer additive may volatilize and no longer bepresent in the same amount in the fibers forming the nonwoven, It isalso believed that some of the softness enhancer additive may migratefrom the interior portion of the fiber to the outer surface of thefiber. Without intending to be bound by any theory, it is believed thatthis migration of the additive to the outer surface of the fiber maycontribute to the perception of softness that a user experiences whenshe touches the nonwoven material.

In one embodiment, the softness enhancer additive is an organic aminecompound, i.e., contains an amine group bound to a hydrocarbon group. Inanother embodiment, the softness enhancer additive is a fatty acid amineor a fatty acid amide. In some embodiments, the softness enhanceradditive may have one or more paraffinic or olefinic groups bound to anitrogen atom, forming an amine or an amide compound. The paraffinic orolefinic group may be, for example, a polar or ionic moiety as a sidechain or within the amine/amide backbone. Such polar or ionic moietiescan include hydroxyl groups, carboxylate groups, ether groups, estergroups, sulfonate groups, sulfite groups, nitrate groups, nitritegroups, phosphate groups, and combinations thereof.

In one embodiment, the softness enhancer additive is an alkyl-etheramine having the formula (R′OH)3-xNRx, wherein R is selected from thegroup consisting of hydrogen, C1-40 alkyl radicals, C2-40 alkylethers,C1-40 alkylcarboxylic acids, and C2-40 alkylesters; R′ is selected fromthe group consisting of C1-40 alkyl radicals, C2-40 alkylethers, C1-40carboxylic acids, and C2-40 alkylesters; and x is 0, 1, 2 or 3,preferably 0 or 1, more preferably 1. In one embodiment, R is selectedfrom the group consisting of hydrogen and C5-40 alkyl radicals; and R′is selected from the group consisting of C5-40 alkyl radicals and C5-40alkylethers.

In another embodiment, the softness enhancer additive is anamide-containing compound having the formula: RCONH2, wherein R is aC5-23 alkyl or alkene. In another embodiment, the softness enhanceradditive is a fatty acid amide having the formula: (R′CO)3-xNR“x,wherein R” is selected from the group consisting of hydrogen, C10-60alkyl radicals and C10-60 alkene radicals and substituted versionsthereof; R′ is selected from the group consisting of C10-60 alkylradicals, C10-60 alkene radicals, and substituted versions thereof; andx is 0, 1, 2 or 3, preferably 1 or 2, more preferably 2. As used herein,an “alkene” radical is a radical having one or more unsaturateddouble-bonds in the radical chain (e.g.,—CH2CH2CH2CH2CH═CHCH2CH2CH2CH.sub—.2CH2CH3), and “substituted” meanssubstitution anywhere along the hydrocarbon chain of a hydroxyl group,carboxyl group, halide, or sulfate group.

In some embodiments, the softness enhancer additive contains anunsaturated amide. In one embodiment, the unsaturated amide-containingsoftness enhancer additive has the formula: RCONH2, wherein R is a C5-23alkene. In another embodiment, the unsaturated amide-containing softnessenhancer additive has the formula: (R′CO)3-xNR“x, wherein R” is selectedfrom the group consisting of hydrogen, C10-60 alkyl radicals and C10-60alkene radicals and substituted versions thereof; R′ is selected fromthe group consisting of C10-60 alkene radicals and substituted versionsthereof; and x is 0, 1, 2 or 3, preferably 1 or 2, more preferably 2. Insome embodiments, the unsaturated amide-containing softness enhanceradditive is at least one of palmitoleamide, oleamide, linoleamide, orerucamide. In other embodiments, the unsaturated amide-containingsoftness enhancer additive is at least one of oleamide or erucamide. Inthe preferred embodiment the softness enhancer additive containserucamide.

Non-limiting examples of softness enhancer additives includebis(2-hydroxyethyl) isodecyloxypropylamine, poly(5)oxyethyleneisodecyloxypropylamine, bis(2-hydroxyethyl) isotridecyloxypropylamine,poly(5)oxyethylene isotridecyloxypropylamine, bis(2-hydroxyethyl) linearalkyloxypropylamine, bis(2-hydroxyethyl) soya amine, poly(15)oxyethylenesoya amine, bis(2-hydroxyethyl) octadecylamine, poly(5)oxyethyleneoctadecylamine, poly(8)oxyethylene octadecylamine, poly(10)oxyethyleneoctadecylamine, poly(15)oxyethylene octadecylamine, bis(2-hydroxyethyl)octadecyloxypropylamine, bis(2-hydroxyethyl) tallow amine,poly(5)oxyethylene tallow amine, poly(15)oxyethylene tallow amine,poly(3)oxyethylene-1,3-diaminopropane, bis(2-hydroxyethyl) cocoamine,bis(2-hydroxyethyl)isodecyloxypropylamine, poly(5)oxyethyleneisodecyloxypropylamine, bis(2-hydroxyethyl) isotridecyloxypropylamine,poly(5)oxyethylene isotridecyloxypropylamine, bis(2-hydroxyethyl) linearalkyloxypropylamine, bis(2-hydroxyethyl) soya amine, poly(15)oxyethylenesoya amine, bis(2-hydroxyethyl) octadecylamine, poly(5)oxyethyleneoctadecylamine, poly(8)oxyethylene octadecylamine, poly(10)oxyethyleneoctadecylamine, poly(15)oxyethylene octadecylamine, bis(2-hydroxyethyl)octadecyloxypropylamine, bis(2-hydroxyethyl) tallow amine,poly(5)oxyethylene tallow amine, poly(15)oxyethylene tallow amine,poly(3) oxyethylene-1,3-diaminopropane, bis(2-hydroxethyl) cocoamine,valeramide, caproicamide, erucamide, caprylicamide, pelargonicamide,capricamide, lauricamide, lauramide, myristicamide, myristamide,palmiticamide, palmitoleamide, palmitamide, margaric (daturic) amide,stearicamide, arachidicamide, behenicamide, behenamide, lignocericamide,linoleamide, ceroticamide, carbocericamide, montanicamide,melissicamide, lacceroicamide, ceromelissic (psyllic) amide,geddicamide, 9-octadecenamide, oleamide, stearamide, tallowbis(2-hydroxyethyl)amine, cocobis(2-hydroxyethyl)amine,octadecylbis(2-hydroxyethyl)amine, oleylbis(2-hydroxyethyl)amine,ceroplastic amide, and combinations thereof.

Commercial examples of useful softness enhancer additives include ATMER®compounds (Ciba Specialty Chemicals), ARMID®, ARMOFILM® and ARMOSLIP®compounds and NOURYMIX concentrates (Akzo Nobel Chemicals), CROTAMID®compounds (Croda Universal Inc), CESA SLIP® compounds (Clariant).Further examples of slip additives include compounds from A. Schulman,Germany, Techmer, USA, or Ampacet, USA.

Compositions useful in the invention may include one or more differentsoftness enhancer additives. For example, in one embodiment acomposition may contain one or more unsaturated amide-containingsoftness enhancer additives, and in another embodiment one or moreunsaturated amide-containing softness enhancer additives and one or moresaturated amide-containing softness enhancer additives. In someembodiments, a composition includes a combination of low molecularweight (Mw) and thus faster migrating amides, e.g., erucamide oroleamide, and higher molecular weight (Mw) and thus slower migratingamides, e.g., behenamide or stearamide. It should be noted, thatcompounds that are suitable as softness enhancer additives, such as forexample amide additives, may sublimate (i.e. transform directly from asolid state to a gaseous state) when subjected to high temperatures. Oneskilled in the art will appreciate that the sublimation level may dependon the additive temperature and partial pressure of additive vapors overthe surface exposed to the outside environment. One skilled in the artwill also appreciate that the processing temperatures should remainlower than the TGA (i.e. Thermogravimetric analysis) Rapid weight losstemperature of the components. Surprisingly it is been found, that whensoftness enhancer additives of the amide type are added in a spunmelting process, it is advantageous to maintain the process temperaturesat a level well below the TGA Rapid weight loss temperature. Inparticular, it is believed that the temperature of the moltencomposition ahead of the spinnerets should be at least 20° C. lower, oreven 25° C. lower than the TGA Rapid weight loss temperature of thesoftness enhancer additive. The TGA Rapid weight loss temperature forvarious substances can be found for example in “Plastics additives: anindustrial guide” written by Ernest W.Flick.

Without wishing to be bound by theory it is believed that thissublimation of the additive can be caused by particular processconditions during fiber production. As in typical nonwoven manufacturingprocesses, the polymer composition is molten and brought to a particulartemperature, which enables the composition to flow and be extrudedthrough spinnerets in order to form fibers. The newly formed fibers arethen quenched at a much lower temperature by air, which flows againstthe fibers' outer surface. When the molten composition is heated to atemperature, which causes the softness enhancer additive to overheat,and the additive may evaporate/sublimate from the outer surface ofsolidifying fiber. Because of the rapid and constant air flow, thepartial pressure is kept to a relative low level, which favorsevaporation/sublimation of the softness enhancer additive than one wouldotherwise expect from TGA values. The following table providestemperatures for several amides.

TGA Weight Loss of Amides Temperature Temperature when % total whenWeight Rapid Weight Softness Enhancer Weight Loss begins Loss beginsType Additive Loss (° C.) (° C.) Primary Oleamide 99.3 195 250 Erucamide94.8 220 280 Secondary Oleylpalmitamide 11.8 225 300 BisamideEthylenebisoleamide 11.6 220 305

In some embodiments, in addition to including nonwoven 21 formed ofmaterials as described above, the nonwoven may include two or morelayers formed of differing components, as described in, for example,U.S. patent application Ser. Nos. 14/058,376; 14/058,398 and Ser. No.14/058,479. Calender bonding

Spunbonding includes the step of calender-bonding the batt of spunlaidfibers, to consolidate them and bond them together to some extent tocreate a fabric-like structure and enhance mechanical properties e.g.,tensile strength, which may be desirable so the material cansufficiently maintain structural integrity and dimensional stability insubsequent manufacturing processes, and in the final product in use.Calender-bonding may be accomplished by passing the batt through the nipbetween a pair of rotating calender rollers, thereby compressing andconsolidating the fibers in the z-direction to form a web. One or bothof the rollers may be heated, so as to promote plastic deformation,intermeshing and/or thermal bonding/fusion between superimposed fiberscompressed at the nip. The rollers may form operable components of abonding mechanism in which they are urged together by a controllableamount of force, so as to exert the desired compressing force/pressureat the nip. In some processes heating may be deemed unnecessary, sincecompression alone may generate sufficient energy within the fibers toeffect bonding, resulting from rapid deformation and frictional heatgenerated in the fibers as they are urged against each other where theyare superimposed, resulting in plastic deformation and intermeshing, andpossibly thermal bonding/fusion. In some processes an ultrasonic energysource may be included with the bonding mechanism so as to transmitultrasonic vibration to the fibers, again, to generate heat energywithin them and enhance bonding.

One or both of the bonding rollers may have their circumferentialsurfaces machined, etched, engraved or otherwise formed to have thereona pattern of protrusions and recessed areas, so that bonding pressureexerted on the batt at the nip is concentrated at the outward surfacesof the protrusions, and reduced or substantially eliminated at therecessed areas. As a result, an impressed pattern of bonds betweenfibers forming the web, somewhat corresponding to the pattern ofprotrusions on the roller, is formed on the nonwoven web. One roller mayhave a smooth, unpatterned cylindrical surface, and the other may beformed with a pattern as described; this combination will impart apattern on the web somewhat reflecting the pattern on the formed roller.In some examples both rollers may be formed with patterns, and inparticular examples, differing patterns that work in combination toimpress a combination pattern on the web such as described in, forexample, U.S. Pat. No. 5,370,764.

A repeating pattern of protrusions and recessed areas such as, forexample, depicted in FIG. 3A, may be formed onto one roller. The smallershapes depicted in FIG. 3A represent outlines of rhombus- ordiamond-shaped raised surfaces 100 of protrusions, while the areasbetween them represent recessed areas 101. Each protrusion surface maybe imparted with a width W_(pi) (relative the machine direction MD) anda length Lp₁, such that each protrusion surface 100 has an area. Withoutintending to be bound by theory, it is believed that the visual impactof the bond impressions impressed on the web, as well as the tensilestrength, resulting from the protrusion surfaces 100, may be affected bythe area of the protrusion surfaces 100. Accordingly, it is believeddesirable that the average area of the individual protrusion surfaces100 be from 0.74 mm² to 1.12 mm², or from 0.84 mm² to 1.02 mm², or evenfrom 0.88 mm² to 0.98 mm². Protrusion surfaces 100 may have diamondshapes as shown, or may have any other suitable shape, although it isbelieved that a diamond, rectangle, square or oval shape may have thedesirable effect of simulating the appearance of stitching, as in aquilt.

As can be seen in FIG. 3A, protrusion surfaces 100 may be arranged suchthat they substantially circumscribe a repeating pattern of recessedareas 101 in the form of geometric shapes. The geometric shapes may becontiguously arranged as depicted. The geometric shapes may be diamondsor squares, as depicted (and illustrated by dotted outlines 102 a, 103 ain FIG. 3A), or may have other shapes, including but not limited totriangles, diamonds, parallelograms, other polygons, circles, hearts,moons, etc. In FIG. 3A, it can be seen also that the pattern ofgeometric shapes repeats in the machine and cross directions atfrequencies determined by the dimensions of the shape circumscribed byoutline 103 a, where outline 103 a is drawn through the centers of theprotrusion surfaces 100. It can be seen that the dimensions of the shapecircumscribed by outline 103 a correspond with shape length L_(S1) andshape width W_(S1) as shown in FIG. 3A. (Again, length and width aredesignated with reference to the machine direction MD.) Withoutintending to be bound by theory, within the ranges of basis weights ofspunbond nonwoven materials contemplated herein, it is believed that thesize of the repeating geometrically-shaped recessed areas 101 may beimpactful with respect to optimizing both the apparent and actualdesired visible “pop” of the pattern.

It may be desired that the shapes circumscribed by the bond impressionsrepeat at a frequency of from 99 to 149, or from 105 to 143, or evenfrom 111 to 137 per meter, in either or both the machine and crossdirections, on the nonwoven web. Referring to FIG. 3B, for example, thiswould means that length L_(S2) and/or width W_(S2) may each be about 6.7mm to 10.1 mm, or from 7.0 mm to 9.5 mm, or even from 7.3 mm to 9 mm.Alternatively, it may be desired that the repeating shapes defined bythe bond impressions (for example, as illustrated/suggested by therepeating square or diamond shape defined by outline 103 a, FIG. 3A),have areas from 52 mm² to 78 mm², or from 55 mm² to 75 mm², or even from58 mm² to 72 mm².

As noted, calender-bonding may be used to consolidate the spunlaid fiberbatt into a fabric-like nonwoven web and to impart mechanical strength,e.g., tensile strength, to the web. Generally, within the rangescontemplated herein, greater percentages of protrusion surface area tototal patterned roller surface area on a roller formed with a givenpattern impart greater tensile strength to the web, than lesserpercentages. However, this may come at the cost of added stiffness inthe web, which may negatively impact tactile softness attributes. It isbelieved that a suitable balance between imparting sufficient tensilestrength for subsequent processing and satisfactory structural strengthin the finished product, and preserving tactile softness attributes, maybe struck when the ratio of area of the protrusion surfaces (e.g.,protrusion surfaces 100, FIG. 3A) to the total patterned roller surfacearea is at least 10%, preferably not more than 20%, more preferably 10%to 17%, and even more preferably 10% to 15%.

It will be noted in FIG. 3A that protrusion surfaces 100 appear to forminterrupted paths, in the example depicted, along directions indicatedby arrows 104 a, 104 b. Without intending to be bound by theory, it isbelieved that the interruptions provide at least two beneficial effects.First, it is believed that the resulting bond impressions in the webhave the effect of simulating the appearance of stitching, as in aquilt. Second, it is believed that the interruptions in the bond pathsprovide a multitude of natural hinge points at which the web may flexabout the discrete bonds, helping to preserve or enhance pliability inthe web despite the presence of the bonds. When a spunlaid batt ispassed through a nip formed by a calendering roller having the patterndepicted in FIG. 3A, bonds among and between the fibers are formedbeneath protrusion surfaces 100. If these surfaces were continuous alongdirections 104 a, 104 b instead of interrupted as shown, the resultingbonds would also be substantially continuous along those directions.This could cause the resulting nonwoven web to be more stiff and lesspliable, undesirably comprising its tactile softness attributes.

It will also be noted in FIG. 3A that the directions 104 a, 104 bfollowed by the bonding pattern paths may be diagonal with respect tothe machine direction. The bond paths imposed on the resulting web willbe similarly diagonal with respect to the machine direction. Withoutintending to be bound by theory, and relative to the use of increasedcalender-bonding pressure and/or roller temperature to form more fullydeveloped bonds as described herein, it is believed that these paths,when formed of more fully-developed bonds, comprise diagonal paths orlinear zones along which the nonwoven web has relatively higher tensilestrength and resistance to elongation. It is believed that aninteresting effect may result. When these paths are diagonal relativethe machine direction and in a criss-crossing pattern as depicted, anet-like structure may be present within the web. As a result, drawingthe nonwoven web under tension in the machine direction (as it would bedrawn in downstream manufacturing processes, e.g., laminating thenonwoven with a polymer film to form backsheet material) may have theeffect of causing the geometric shapes 101 to slightly protrude or “pop”in the z-direction out of the general plane of the web material surfaceas it narrows in width (exhibiting Poisson effect behavior), or “necks”slightly, as a result of forces within the material under tension in themachine direction, influenced by the net-like structure of diagonalpaths of higher tensile strength formed by the bonds.

It is believed that a pattern of diagonally-oriented bonding paths, assuggested in FIGS. 3A and 3B, may be more effective for producing thez-direction “pop” effect described above, than other possibleconfigurations. It is believed, further, that along suchdiagonally-oriented bonding paths, a greater percentage of bondedmaterial along the paths will have a more dramatic impact than a lesserpercentage, because the bonding results in the above-mentioned effect offorming a line along the nonwoven of relatively greater tensile strengthand resistance to elongation. Thus, referring to FIG. 3B, it can be seenthat a line 105 can be traced a path of bond impressions 100 a (line 105is drawn through the centers of bond impressions 100 a, in the depictedexample). In order that path 105 exhibits sufficiently greater tensilestrength and resistance to elongation than neighboring/parallel lines orpaths in the material, it may be desirable that the Bond Length Ratio ofa segment along line 105 is between 35% and 99%. However, as noted, itmay be desirable not to impart too much stiffness to the web (whichcompromises a tactile softness attribute). Thus, it may be desirablethat the Bond Length Ratio of a bond path be between 35% and 80%, morepreferably between 35% and 65%, and even more preferably between 35% and55%.

It has been learned that more fully-developed bonds and a morehighly-defined bond pattern may be more effectively achieved when theprotrusion surfaces 100 are polished such that they are relativelysmooth, rather than having a rougher, machined surface.

In order to complement the z-direction “pop” effect, in which thematerial forming unbonded areas 101 a protrudes out of the general planeapproximated by the web surface, it may be desirable that the pattern ofbond impressions 100 a (e.g., FIG. 3B) be distinct to the naked eye. Inorder to achieve this, sufficient force between the calendering rollersshould be applied, in combination with sufficient heating temperature.As a result, a visibly distinct pattern of bonds may be achieved, andthis pattern will have measurable features. Depending upon bondingpressure and temperature used, the shape and area of the protrusionsurfaces 100 will be somewhat reflected in the shape and area of thebond impressions in the nonwoven web. Generally it may be desired thatcalender bonding pressure and/or roller temperature be adjusted so as tocause the shape and area of protrusion surfaces 100 to be substantiallyreflected in the shape and area of the bond impressions.

It was previously believed that relatively lighter calender bondingpressures and/or relatively cooler bond roller temperatures wererequired for calender bonding, to avoid tightly binding down fibers,such that they were no longer available to be fluffed by downstreamhydroengorging processes intended to enhance visual and tactile softnessattributes. Similarly, while creating more fully developed bonds wasthought to be required to improve tensile strength properties, it wasbelieved that creating more fully-developed, rigid bonds throughrelatively greater calendering pressures and/or roller temperatureswould have the effect of undesirably increasing stiffness of thenonwoven, unacceptably compromising its tactile softness attributes. Inshort, it was believed that to preserve or gain tactile and visualsoftness signals, it was necessary to compromise tensile strength.

However, it has been discovered, surprisingly, that under thecircumstances and conditions described herein, negative effects ofgreater bonding pressures and/or temperatures upon tactile softnessattributes may be insubstantial and/or may be overcome by the positiveeffects upon visual softness attributes. More particularly, it has beendiscovered that a more highly-defined bond pattern and quilt “pop” maybe enabled through use of relatively increased calender bondingpressures and/or roller temperatures, resulting in more fully-developedbonds, which appears to be effective at creating a product that createsoverall visual impressions of softness that may overcome any negativeeffects upon tactile softness signals resulting from increased stiffnessin the material.

Further, it has been discovered, surprisingly, that one tactile softnesssignal, pliability (sometimes known as “drape”), can be substantiallymaintained or only insubstantially affected with the nonwoven materialsunder circumstances contemplated herein, even where more fully developedbonds are created, using bond patterns having features such as thosedescribed above. Without intending to be bound by theory, it is believedthat interruptions in the bond paths, for example, such as thosedescribed above (e.g., interruptions 106, FIG. 3B), may provide naturalhinge points at which the material may flex easily about bonds, even inthe presence of more fully developed bonds. Although the phenomenon isnot thoroughly understood, it is believed that this hinge effect,combined with the multitude of relatively small bond sites separated byunbonded areas such as described and depicted herein (e.g., unbondedareas 101 a, FIG. 3A), result in effective substantial preservation ofpliability or drape even when the bond sites are more fully developedthrough relatively increased calender bonding pressures and/ortemperatures.

At the same time, creating more fully developed bond sites may addtensile strength in the machine and/or cross directions. Thus,counterintuitively, it has been discovered that tensile strength can besubstantially increased through creation of more fully developedcalender bonds, without a corresponding, deleteriously substantialnegative effect on a tactile softness signal, pliability. This effectmay be achievable using features of roller patterns as described herein,with suitably adjusted calender force/pressure and roller temperature,to impress a Bond Area Percentage in the nonwoven web of at least 10%,preferably not more than 20%, more preferably 10% to 17%, and even morepreferably 10% to 15%.

Referring to FIGS. 3A and 3B by way of example, it is believed that thesize, shape and area of bond impressions 100 a in the nonwoven webproduct will somewhat, but not identically, reflect the size, shape andarea of calender roller protrusion surfaces 100. It is believed that theextent to which the area(s) of bond impressions 100 a reflect thearea(s) of roller protrusion surfaces 100 may be affected by the bondingforce/pressure between the calender rollers at the nip, and/or theroller temperature, and generally, that increasing bondingforce/pressure and/or roller temperature will increase the area of bondimpressions 100 a relative the area of protrusion surfaces 100. Thus, ifthe area of a protrusion surface 100 is from 0.74 mm² to 1.12 mm², orfrom 0.84 mm² to 1.02 mm², or even from 0.88 mm² to 0.098 mm² as setforth above, it is believed that generally the area of a correspondingbond impression will be somewhat less. In order to achieve the visiblyimproved results realized in Example 2 herein, bond impressions 100 awere created having an average surface area of 0.57±0.06 mm², resultingfrom protrusion surfaces 100 having an average surface area ofapproximately 0.93 mm². In a prior version, using the same basis weightspunbond batt and the same rollers, the resulting average bondimpression surface area was measured as 0.27±0.02 mm², resulting from arelatively lighter calender pressure and/or roller temperature. It isbelieved that an increase in calender pressure and/or roller temperatureis at least partially the cause for the difference.

In other embodiments, the web 21 may be bonded using the techniques andpatters described in, for example, U.S. Pat. App. Pub. No. 2013/0253461.

Hydroengorging

Following calender bonding, the web may be subjected to ahydroengorgement process such as described in U.S. Pat. App. Pub. No.2006/0057921. A distinguishing feature of hydroengorgement, as comparedwith traditional hydroentanglement, is the use of hydraulic jets toenhance the loft and softness attributes of a nonwoven. However, prioruse of hydroengorgement has not been fully satisfactory for providing anonwoven having both improved softness and a bond pattern with avisually distinct appearance. The '921 application describes ahydroengorgement process involving particular ranges of pressure, e.g.,180-240 bar (2,610-3,480 p.s.i.) applied to the water jet orifices,which was believed required to obtain a desired amount of fluffing ofthe nonwoven fibers, adding apparent and actual loft or caliper.However, it has been discovered that substantially reducing thehydroengorgement pressure from these magnitudes may still providedesired fluffing without deleterious effects. It is believed thathydroengorgement pressures of the magnitude specified in the '921application may result in a loss of distinctiveness and/or obscuring ofthe pattern of bond impressions. Substantially reducing hydroengorgementpressure and energy, and directing hydroengorgement jets at only theinner-facing surface of the nonwoven (thus urging fibers/portionsthereof impinged by water jets toward the outer-facing surface) appearsto have had a contribution to improving the definition and visual “pop”of the quilt appearance on the outer-facing surface imparted by theroller pattern. A reduced pressure of about 25-100 bars (360-1,450p.s.i.) may be employed for hydraulic treatment. More preferably, twoinjectors, each at about 50 bars (725 p.s.i.) of pressure are used,providing an energy transmission of about 0.02 kwhr/kg. It is believedthat the use of a one-sided hydroengorgement significantly improves thesoftness attributes of the nonwoven while pushing fibers in between bondareas to create a more pronounced appearance. Further, thehydroengorgement may enhance the resilience of the pattern such that itcan maintain a pronounced appearance after being processed into anarticle and packaged.

Test Methods In-Bag Compression Measurement Test I. Determine Free StackHeight Equipment

-   -   Universal Diaper Packaging Tester (UDPT), including a vertical        sliding plate for adding weights. It is counter-balanced by a        suspended weight to assure that no downward force is added from        the vertical sliding plate assembly to the diaper package at all        times. The UDPT is available from Matsushita Industry Co. LTD,        7-21-101, Midorigaoka-cho, Ashiya-city, Hyogo JAPAN, Zip code:        659-0014. For further details concerning this Tester, see U.S.        Pat. App. Pub. No. 2008/0312624.    -   A 850 g (±5 g) weight.    -   Stopwatch with an accuracy to 1 second.

Test Procedure

A) Apparatus Calibration

-   -   Pull down the vertical sliding plate until its bottom touches        the tester base plate.    -   Set the digital meter located at the side of the vertical        sliding scale to zero    -   Raise the vertical sliding plate away from the tester base        plate.

B) Definitions

-   -   Before-bagger free height refers to the free height data        measured on 10 pads of fresh diapers.    -   Fresh Diapers—10 diapers that have never been compressed (stack        should be removed (where safely possible) immediately after exit        from stacker, before any compression has occurred. If this is        not possible, they should be removed from the fingers of a        safely stopped stacker chain).    -   Out-bag free height designates the free height data measured on        10 pads of aged diapers.    -   Aged Diapers—10 diapers that have been held under compression        for approximately 1 minute and/or longer (i.e. 10 diapers come        from a freshly opened diaper package).

C) Free Height Measurement

-   -   Select 10 adjacent pads of diapers out of the middle from an        appropriate source; Fresh diapers for before-bagger free height;        Aged diapers for out-of-bag free height.    -   Neatly stack these 10 pads of diapers underneath the vertical        sliding plate. (Align the center of the top pad directly below        the central counter sunk hole of the vertical sliding plate.)        Place the 850 g weight onto the vertical sliding plate.    -   Allow the vertical sliding plate to slide down until its bottom        lightly touches desired highest point of the stack.    -   Measure the stack dimensions in mm by reading the value that        appears on the digital meter.    -   Remove the weight.    -   Raise the vertical sliding plate away from the stack and remove        the stack.    -   Record the stack height reading to the nearest 1 mm shown on the        digital meter.

Procedure—Aging Profile

A) Collect a minimum of three data points from different sample setse.g., Measure first point from fresh diapers, e.g., measure second pointfrom diapers being aged in bag for 30 mm/1 hr/6 hr/12 hr/24 hr, e.g.,measure third point from diapers being aged in bag for 5 days or longer.

B) Repeat the three steps as described in “Test Procedure” steps A), C),and D).

Procedure—Out-of-Bag Free Height Recovery

A) Collect 10 pads of fresh/aged diapers.

B) Repeat the first two steps as described in “Test Procedure” steps A)and C).

C) Repeat the steps above for general free height measurement exceptchanging the waiting time (i.e., measure first point at 1 min andremaining points at30 mm/1 hr/6 hr/12 hr/I day/3 days/5 days, orlonger).

Calculation/Reporting

-   -   Report Sample Identification, i.e. complete description of        product being tested (product brand name/size).    -   Report the determined value for all measurement to the nearest 1        mm.

NOTE: In case of a series of measurements report the number of testedsamples, and calculate/report the Average, Standard deviation, Minimumand Maximum of the values.

-   -   Report the Production Date of the measured package (taken from        package coding).    -   Report the Testing Date and Analytical Method used (GCAS).        II. Determine in-Bag Stack

Equipment

-   -   Universal Diaper Packaging Tester (UDPT), including a vertical        sliding plate for adding weights. It is counter-balanced by a        suspended weight to assure that no downward force is added from        the vertical sliding plate assembly to the diaper package at all        times. The UDPT is available from Matsushita Industry Co. LTD,        7-21-101, Midorigaoka-cho, Ashiya-city, Hyogo JAPAN, Zip code:        659-0014.    -   A 850 g (±5 g) weight.

DEFINITIONS

-   -   “Package Width” is defined as the maximum distance between the        two highest bulging points along the same compression stack axis        of a diaper package.    -   In-Bag Stack Height=(Package Width I Pad Count Per Stack)×10        pads of diapers.

Apparatus Calibration

-   -   Pull down the vertical sliding plate until its bottom touches        the tester base plate.    -   Set the digital meter located at the side of the vertical        sliding scale to zero mark.    -   Raise the vertical sliding plate away from the tester base        plate.

Test Procedure

-   -   Put one of the side panel of the diaper package along its width        standing at the center of the tester base plate. Make sure the        horizontal sliding plate is pulled to the right so it does not        touch the package being tested.    -   Add the 850 g weight onto the vertical sliding plate.    -   Allow the vertical sliding plate to slide down until its bottom        lightly touches desired highest point of the package.    -   Measure the package width in mm (distance from the top of the        base plate to the top of the diaper package). Record the reading        that appears on the digital meter.    -   Remove the 850 g weight.    -   Raise the vertical sliding plate away from the diaper package.    -   Remove the diaper package.

Calculation/Reporting

-   -   Calculate and report the “In-Bag Stack Height”=(Package Width I        Pad Count Per Stack)×10.    -   Report Sample Identification, i.e. complete description of        product being tested (product brand name/size).    -   Report the determined value for each measurement        (Length/Width/Front-to-Back) to the nearest 1 mm.

NOTE: In case of a series of measurements report the number of testedsamples, and calculate/report the Average, Standard deviation, Minimumand Maximum of the values.

-   -   Report the Production Date of the measured package (taken from        package coding).    -   Report the Testing Date and Analytical Method used (GCAS).

III. Calculate %

-   -   Calculate %: 1-(In-Bag Stack Height)/(Free Stack Height)=%

Opacity Measurement Method

The opacity of a material is the degree to which light is blocked bythat material. A higher opacity value indicates a higher degree of lightblock by the material. Opacity may be measured using a 0°illumination/45° detection, circumferential optical geometry,spectrophotometer with a computer interface such as the HunterLabLabScan XE running Universal Software (available from Hunter AssociatesLaboratory Inc., Reston, Va.). Instrument calibration and measurementsare made using the standard white and black calibration plates providedby the vendor. All testing is performed in a room maintained at about23±2° C. and about 50±2% relative humidity.

Configure the spectrophotometer for the XYZ color scale, D65 illuminant,10° standard observer, with UV filter set to nominal. Standardize theinstrument according to the manufacturer's procedures using the 1.20inch port size and 1.00 inch area view. After calibration, set thesoftware to the Y opacity procedure.

To obtain the specimen, lay the sample flat on a bench, body facingsurface downward, and measure the total longitudinal length of thearticle. Note a site 33% of the total length from the front waist of thearticle along the longitudinal axis and a second site, 33% of the totallength from the back waist of the article. Carefully remove thebacksheet laminate, consisting of both the film and nonwoven web, fromthe garment-facing side of the article. A cryogenic spray, such asCyto-Freeze (obtained from Control Company, Houston, Tex.), may be usedto separate the backsheet laminate from the article. Cut a piece 50.8 mmby 50.8 mm centered at each site identified above. Precondition samplesat about 23° C.±2 C.° and about 50%±2% relative humidity for 2 hoursprior to testing.

Place the specimen over the measurement port. The specimen shouldcompletely cover the port with the surface corresponding to thegarment-facing surface of the article directed toward the port. Coverthe specimen with the white standard plate. Take a reading, then removethe white tile and replace it with black standard tile without movingthe specimen. Obtain a second reading, and calculate the opacity asfollows:

Opacity=Y Value_((black backing)) /Y ValUe_((white backing))×100

A total of five identical articles are analyzed and their opacityresults recorded. Calculate and report the average opacity and standarddeviation for the 10 backsheet laminate measurements to the nearest0.01%.

Using the same specimens as above, remove the nonwoven web from the filmlayer for analysis. The cryogenic spray can once again be employed.Precondition samples at about 23° C.±2 C.° and about 50%±2% relativehumidity for 2 hours prior to testing. In like fashion, analyze thenonwoven web layer following the above procedure. Calculate and reportthe average opacity and standard deviation for the 10 nonwoven webmeasurements to the nearest 0.01%.

Average Measured Height Method

Average Measured Height is measured using a GFM Primos Optical Profilerinstrument commercially available from GFMesstechnik GmbH,Teltow/Berlin, Germany. The GFM Primos Optical Profiler instrumentincludes a compact optical measuring sensor based on digitalmicro-mirror projection, consisting of the following main components: a)DMD projector with 1024×768 direct digital controlled micro-mirrors; b)CCD camera with high resolution (1300×1000 pixels); c) projection opticsadapted to a measuring area of at least 27×22 mm; d) recording opticsadapted to a measuring area of at least 27×22 mm; e) a table tripodbased on a small hard stone plate; f) a cold light source (anappropriate unit is the KL 1500 LCD, Schott North America, Inc.,Southbridge, Mass.); g) a measuring, control, and evaluation computerrunning ODSCAD 4.14-1.8 software; and h) calibration plates for lateral(x-y) and vertical (z) calibration available from the vendor.

The GFM Primos Optical Profiler system measures the surface height of asample using the digital micro-mirror pattern fringe projectiontechnique. The result of the analysis is a map of surface height (zaxis) versus displacement in the x-y plane. The system has a field ofview of 27×22 mm with a resolution of 21 microns. The height resolutionshould be set to between 0.10 and 1.00 micron. The height range is64,000 times the resolution. All testing is performed in a conditionedroom maintained at about 23±2° C. and about 50±2% relative humidity.

To obtain the specimen, lay the sample flat on a bench, body facingsurface downward, and measure the total longitudinal length of thearticle. Note a site 33% of the total length from the front waist of thearticle along the longitudinal axis and a second site, 33% of the totallength from the back waist of the article. Carefully remove the nonwovenouter cover from the garment-facing side of the article. A cryogenicspray, such as Cyto-Freeze (obtained from Control Company, Houston,Tex.), may be used to separate the nonwoven from the underlying filmlayer. Cut a piece 40 mm by 40 mm centered at each site identifiedabove. Precondition samples at about 23° C.±2 C.° and about 50%±2%relative humidity for 2 hours prior to testing.

Turn on the cold light source. Select settings on the cold light sourceto give a reading of 3000K on the display (typically 4 and E). Open theODSCAD 4.14-1.8 Software and select “Start Measurement” and then “LivePic”. Calibrate the instrument according to manufacturer'sspecifications using the calibration plates for lateral (x-y) andvertical (z) available from the vendor.

Place the 40 mm by 40 mm specimen of nonwoven outer cover, clothingsurface upward, under the projection head and on top of a neutral graysurface (WhiBal White Balance Reference, PictureFlow LLC, Melbourne,Fla.). Ensure that the sample is lying flat, without being stretched.This may be accomplished by taping the perimeter of the sample to thesurface or placing it under a weighted frame with an inside dimension of30 mm×30 mm.

Using the “Pattern” command, project the focusing pattern on the surfaceof the specimen. Position the projection head to be normal to the samplesurface. Align the projected cross hair with the cross hair displayed inthe software. Focus the image using the projector head height adjustmentknob. Adjust image brightness according to the instrument manufacturer'sinstruction by setting the “Projection” value to 10, and then changingthe aperture on the lens through the hole in the side of the projectorhead. Optimum illumination is achieved when the lighting displayindicator in the software changes from red to green. Due to variationsin instrument configurations, different brightness parameters may beavailable. Always follow the instrument manufacturer's recommendedprocedures for proper illumination optimization.

Select the Technical Surface/Standard measurement type. Operatingparameters are as follows: Utilization of fast picture recording with a3 frame delay. A two level Phasecode, with the first level being definedas an 8 pixel strip width with a picture count number of 24, and thesecond level being defined as a 32 pixel strip width with a picturecount number of 6. A full Graycode starting with pixel 1 and ending withpixel 1024. A Prefiltering routine including the removal of invalidpixels, a 5 by 5 median filter, and a 3 by 3 average filter.

Select “Measure” to capture and digitalize the image. The specimen mustremain still during this procedure to avoid blurring of the capturedimage. The image will be captured in approximately 20 seconds. Save theheight image and camera image files.

Load the height image into the analysis portion of the software via theclipboard. Zoom in on a region of interest (ROI) encompassing a singlerepeating pattern of bond impressions and unbonded area. Using thepolygon drawing tool manually outline four individual bond impressionsaround the perimeter of the unbonded area (see example in FIG. 4B). From“View” select “Histogram of height picture”. Select the number ofclasses as 200 and calculate the frequency histogram. Save the bondimpression height file. Returning to the height image, cancel thepolygon markings drawn on the bond impressions. Next, using the polygondrawing tool, manually outline the unbonded area surrounded by the bondimpressions (see example in FIG. 4A). Once again, from “View” select“Histogram of height picture”. Select the number of classes as 200 andcalculate the frequency histogram. Save the unbonded area histogramfile.

Open the histogram file of the bond impressions, determine the heightrange value at, or nearest to 50%. Record bond impression height to thenearest 1 micrometer. Open the histogram file of the unbonded area,determine the height range value at, or nearest to 90%. Record theunbonded area height to the nearest 1 micrometer. Measured Height iscalculated as follows:

Measured Height=unbonded area height−bond impression height

Measured Height is measured at two separate ROI's for each of thespecimens (i.e., from front of article and back of article) to give fourmeasures per test article. A total of three test articles are analyzedin like fashion. Calculate the Average and standard deviation for alltwelve Measured Heights and report to the nearest 1 micrometer.

Tensile Strength Measurement Method

Tensile Strength is measured on a constant rate of extension tensiletester with computer interface (a suitable instrument is the MTSAlliance using Testworks 4.0 Software, as available from MTS SystemsCorp., Eden Prairie, Minn.) using a load cell for which the forcesmeasured are within 10% to 90% of the limit of the cell. Both themovable (upper) and stationary (lower) pneumatic jaws are fitted withrubber faced grips, wider than the width of the test specimen. Alltesting is performed in a conditioned room maintained at about 23° C.±2C and about 50%±2% relative humidity.

To obtain the specimen for CD tensile, lay the sample flat on a bench,body facing surface downward, and measure the total longitudinal lengthof the article. Note a site 25% of the total length from the front waistof the article along the longitudinal axis and a second site, 25% of thetotal length from the back waist of the article. Carefully remove thenonwoven outer cover from the garment-facing side of the article. Acryogenic spray, such as Cyto-Freeze (obtained from Control Company,Houston, Tex.), may be used to separate the nonwoven outer cover fromthe underlying film layer. Cut a specimen, with a die or razor knife,which is 50.8 mm wide along the longitudinal axis of the sheet and least101.6 mm long along the lateral axis of the sheet, centered at each ofthe sites identified above.

In like fashion prepare MD tensile specimens from a second set ofidentical samples.

Here, after removing the nonwoven outer cover, cut a specimen, with adie or razor knife, which is at least 101.6 mm wide along thelongitudinal axis of the sheet and 50.8 mm long along the lateral axisof the sheet, centered at each of the sites identified above.Precondition both CD and MD specimens at about 23° C.±2 C.° and about50%±2% relative humidity for 2 hours prior to testing.

For analyses, set the gage length to 50.8 mm. Zero the crosshead andload cell. Insert the specimen into the upper grips, aligning itvertically within the upper and lower jaws and close the upper grips.Insert the specimen into the lower grips and close. The specimen shouldbe under enough tension to eliminate any slack, but less than 0.05 N offorce on the load cell.

Program the tensile tester to perform an extension test, collectingforce and extension data at an acquisition rate of 50 Hz as thecrosshead raises at a rate of 100 mm/min until the specimen breaks.Start the tensile tester and data collection. Program the software torecord Peak Force (go from the constructed force (go verses extension(mm) curve. Calculate tensile strength as:

Tensile Strength=Peak Force(gf)/width of specimen(cm)

Analyze all CD tensile specimens. Record Tensile Strength to the nearest1 gf/cm.

Analyses are performed on specimens from the two sites on the article. Atotal of five test articles are analyzed in like fashion. Calculate andreport the average and standard deviation of Tensile Strength to thenearest 1 gf/cm for all ten measured CD specimens.

Next run all MD tensile Specimens. Record Tensile Strength to thenearest 1 gf/cm. Analyses are performed on specimens from the two siteson the article. A total of five test articles are analyzed in likefashion. Calculate and report the average and standard deviation ofTensile Strength to the nearest 1 gf/cm for all ten measured MDspecimens.

Image Analysis of Bond Impressions

Area and distance measurements are performed on images generated using aflat bed scanner capable of scanning at a resolution of at least 4800dpi in reflectance mode (a suitable scanner is the Epson Perfection V750Pro, Epson, USA). Analyses are performed using ImageJ software (Vs.1.43u, National Institutes of Health, USA) and calibrated against aruler certified by NIST.

To obtain the specimen, lay the sample flat on a bench, body facingsurface downward, and measure the total longitudinal length of thearticle. Note a site 33% of the total length from the front waist of thearticle along the longitudinal axis and a second site, 33% of the totallength from the back waist of the article. Carefully remove the nonwovenouter cover from the garment-facing side of the article. A cryogenicspray, such as Cyto-Freeze (obtained from Control Company, Houston,Tex.), may be used to separate the nonwoven from the underlying filmlayer. Cut a piece 80 mm by 80 mm centered at each site identifiedabove. Precondition samples at about 23° C.±2 C.° and about 50%±2%relative humidity for 2 hours prior to testing.

Place the specimen on the flat bed scanner, body side surface facingupward, with the ruler directly adjacent. Placement is such that thedimension corresponding to the MD of the nonwoven is parallel to theruler. A black backing is placed over the specimen and the lid to thescanner is closed. Acquire an image composed of the nonwoven and rulerat 4800 dpi in reflectance mode in 8 bit grayscale and save the file.Open the image file in ImageJ and perform a linear calibration using theimaged ruler. Reference will be made to FIG. 3B as an example of arepeating pattern of bond impressions. These measures are equallyapplicable to other bond shapes and repeating bond patterns.

Average Individual Bond Area

Enlarge a ROI such that edges of the bond impression can be clearlydetermined. With the area tool, manually trace the perimeter of a bond.Calculate and record the area to the nearest 0.001 mm². Repeat for atotal of ten non-adjacent bonds randomly selected across the totalspecimen. Measurements are made on both specimens from each article. Atotal of three identical articles are measured for each sample set.Calculate the average and standard deviation of all 60 bond areameasurements and report to the nearest 0.001 mm².

Bond Path/Bond Length Ratio

Identify a single, complete repeating series of bond impressions forminga path and enlarge the image such that the repeating series fills thefield of view. Draw a line along the path that connects and extendsthrough all bond impressions in the series (e.g., FIG. 3B, line 105).Measure the dimensions along the line that are included within the bondimpressions (e.g. in FIG. 3B, D₁, D₂, D₃). Next, measure the distance ofthe line segment from the leading edge of the first bond impression inthe repeating series to leading edge of the first bond impression in thenext adjacent series along the line segment (e.g. in FIG. 3B, D₀).Calculate the sum of the lengths of the bonds along the line segment(e.g. D₁+D₂+D₃), divided by the length of the line segment, (e.g.D₀),×100%. Record the Bond Path/Bond Length Ratio to the nearest 0.001.Repeat for a total of five non-adjacent ROI's randomly selected acrossthe total specimen. Measurements are made on both specimens from eacharticle. A total of three identical articles are measured for eachsample set. Calculate the average and standard deviation of all 60 bondPath/Length Ratio measurements and report to the nearest 0.001 units.Note for irregularly-shaped bond impressions forming a repeating series,locate a line so as to find the maximum sum of the lengths of the bondimpressions measurable therealong.

Bond Area Percentage

Identify a single repeat pattern of bond impressions and unbonded areasand enlarge the image such that the repeat pattern fills the field ofview. In ImageJ draw a box that encompasses the repeat pattern. For theexample shown in FIG. 3B, this would be a box, W_(S2) wide and L_(K)long. Note, in the example shown in FIG. 3B, the shared bond impressionsat the corners are divided in half along the longitudinal or lateraldirection as appropriate. Calculate area of the box and record to thenearest 0.01 mm². Next, with the area tool, trace the individual bondimpressions or portions thereof entirely within the box and calculatethe areas of all bond impressions or portions thereof that are withinthe box. Record to the nearest 0.01 mm². Calculate as follows:

Percent Bond Area=(Sum of areas of bond impressions within box)/(area ofbox)×100%

Repeat for a total of five non-adjacent ROI's randomly selected acrossthe total specimen. Record as Percent Bond Area to the nearest 0.01%.Measurements are made on both specimens from each article. A total ofthree identical articles are measured for each sample set. Calculate theaverage and standard deviation of all 30 of the percent bond areameasurements and report to the nearest 0.001 units.

Stiffness

Stiffness of the nonwoven outer cover was measured in accordance withASTM D6828-02. For analysis a 76.2 mm by 76.2 mm square specimen wasused instead of the 100 mm by 100 mm specimen recited in the standard.

To obtain the specimen, lay the sample flat on a bench, body facingsurface downward, and measure the total longitudinal length of thearticle. Note a site 25% of the total length from the front waist of thearticle along the longitudinal axis and a second site, 25% of the totallength from the back waist of the article. Carefully remove the nonwovenouter cover from the garment-facing side of the article. A cryogenicspray, such as Cyto-Freeze (obtained from Control Company, Houston,Tex.), may be used to separate the nonwoven from the underlying filmlayer. Cut a piece 76.2 mm by 76.2 mm centered at each site identifiedabove. Precondition samples at about 23° C.±2 C.° and about 50%±2%relative humidity for 2 hours prior to testing.

Stiffness measurements are made on both specimens from each article. Atotal of three identical articles are measured for each sample set.Calculate the average and standard deviation of the six Total Stiffnessresults and report to 0.01 g.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A nonwoven web, formed of spunlaid fiberscomprising a first polyolefin, a second polyolefin, and a softnessenhancer additive; wherein the second polyolefin is a propylenecopolymer and is a different polyolefin than the first polyolefin,wherein the nonwoven web is impressed with a first pattern of bondimpressions, the first pattern of bond impressions defining a secondpattern of unbonded raised regions, and the nonwoven web has undergone ahydroengorgement process following a calendar bonding process.
 2. Thenonwoven web of claim 1 wherein substantially all of the spunlaid fibersare monocomponent fibers.
 3. The nonwoven web of claim 1 wherein thefirst pattern of bond impressions comprises at least two adjacent,parallel, straight paths defined by the bond impressions, wherein a lineexists along each path, along which there are bonded lengths separatedby unbonded lengths, and the ratio of total bonded length to totalunbonded length (Bond Length Ratio) is at least 35% but less than 100%.4. The nonwoven web of claim 1 wherein the bond impressions constitute aBond Area Percentage of at least 10%.
 5. The nonwoven web of claim 4wherein the Bond Area Percentage is no more than 20%.
 6. The nonwovenweb of claim 1 wherein said second polyolefin is a propylene ethylenecopolymer with between 5% and 35% of ethylene units.
 7. The nonwoven webof claim 1 wherein said calendering bonds provide said nonwoven materialwith a first textured surface and a second surface opposite said firstsurface.
 8. The nonwoven web of claim 1 wherein said composition used tomake said fibers comprises between 5% and 25% by weight of said secondpolyolefin and between 0.01% to 10% softness enhancer additive by weightof said fibers.
 9. The nonwoven web of claim 1 wherein said firstpolyolefin comprises polypropylene and said second polyolefin comprisesan elastomeric polypropylene.
 10. The nonwoven web of claim 1 whereinsaid nonwoven material has a basis weight of between 6 g/m² and 50 g/m2.11. The nonwoven web of claim 10 wherein said nonwoven material has acaliper of between 0.15 mm and 1 mm.
 12. The nonwoven web of claim 1wherein said softness enhancer additive comprises at least one ofoleamide, erucamide, and or stearamide.
 13. The nonwoven web of claim 1,wherein said propylene copolymer has a triad tacticity of threepropylene units, as measured by 13C NMR according to description of atleast about 75%, at least about 80%, at least about 82%, at least about85%, or at least about 90%
 14. The nonwoven web of claim 1, wherein thesoftness enhancer additive comprises chemical compounds having anitrogen bond to organic chain, preferably being organic amine or amide.15. An absorbent article comprising a topsheet, a backsheet and anabsorbent core disposed therebetween, the absorbent article having acomponent comprising the nonwoven web of claim
 1. 16. The absorbentarticle of claim 15 wherein the component is the topsheet.
 17. Theabsorbent article of claim 15 wherein the component is the backsheet.18. The absorbent article of claim 17 wherein the backsheet is formed ofa laminate including a liquid impermeable film.